The present invention relates to the incorporation of fibriform material comprising smoke-modifying agents in smoking material rods.
It has heretofore been proposed to incorporate a filament comprising smoke-modifying agents in a smoking material rod, such as a tobacco rod. For example, in GB 2 070 409 it was proposed that a filament comprising smoke-modifying agents be incorporated in the smoking material rod by insertion of the filament at the tongue of the garniture of a tobacco rod making machine. As would be apparent to those skilled in the art, insertion of a filament at the tongue of the garniture would inevitably require bending of the filament, which bending may be undesirable under certain circumstances, such as when a filament of lesser flexibility is used. Furthermore, when inserting filaments at the tongue of the garniture, the precise location of the filament laterally of the resulting tobacco rod is not easily regulated and also, disadvantageously, the flow of tobacco at the garniture could be disturbed.
U.S. Pat. No. 5,144,966 discloses a flavourant-release additive in the form of a filament for incorporation in the combustible filler of cigarette products and a method of production of such a filament. In U.S. Pat. No. 5,144,966at Column 3, lines 20-23 it is stated, in respect of the incorporation of filaments in filler rod during formulation of the rod on a rod making machine, that the filament, on a reel module, can be fed continuously to the moving cigarette wrapper strip in co-ordination with the combustible filler feed stream. As is well known to those persons skilled in the art, in cigarette manufacture the cigarette wrapper strip is fed directly into the garniture of the tobacco rod making machine. U.S. Pat. No. 5,144,966 clearly teaches that the filament is fed to the moving cigarette wrapper strip and thus that the filament is fed to the garniture of the tobacco rod making machine, much in the same manner as that disclosed in GB 2 070 409 above. The disadvantages of such a system, as outlined above, include the lateral positioning of the filament in the completed tobacco rod being substantially unregulated and the introduction of inflexible filaments being difficult.
The present invention is predicated upon Applicant""s realisation that it is important that when a smoke-modifying agent is incorporated in a tobacco rod such as to be distributed along the rod, the agent is located at an axial zone of the rod. Such axial zone location of the agent ensures maximal transfer efficiency of the agent into mainstream smoke. Furthermore, the location of the agent at an axial zone of the rod ensures a minimal propensity of spot formation on the tobacco rod wrapper. In addition, ash formation in cigarettes comprising a tobacco rod having a smoke-modifying agent at an axial zone thereof resembles that of conventional cigarettes.
U.S. Pat. No. 4,219,031 teaches a method of making a smoking article, which smoking article comprises a gas permeable, self-supporting central core consisting essentially of a carbonised cellulose rod, which core is circumscribed by tobacco. Reference is made in Column 5, line 19 to the feeding of a carbonised rod into cigarette fabricating equipment, which equipment, it is said, acts to arrange cut tobacco shreds around the periphery of the core (rod). However, there is no teaching as to how this could be achieved practically.
Finally, in U.S. Pat. No. 4,727,888 a method is disclosed for making a smoking article rod, for which method two tobacco rod making machines are juxtaposed with the respective garnitures in alignment. The first making machine produces a tobacco rod the diameter of which is smaller than that of a conventional cigarette. This small diameter tobacco rod is then fed from the first making machine directly into the second making machine, in which further tobacco is fed to and around the small diameter rod and a paper wrapper is applied about the layer of further tobacco, thus to form a coaxial tobacco rod of conventional exterior circumferential dimension.
It is an object of the present invention to provide for fibriform smoke-modifying material in a smoking material rod.
The present invention provides, according to a first aspect thereof, a method of incorporating fibriform smoke-modifying material in smoking material rod, wherein fibriform smoke-modifying material is fed longitudinally thereof to a rod making machine, the longitudinal feed path in said machine being in a travel direction of the smoking material deposition run of the suction band of said machine, said feed path of said fibriform smoke-modifying material being caused to ascend towards said deposition run under the influence of the suction force towards said run until at a predetermined distance along said deposition run said fibriform material becomes supported and is subsequently maintained at a predetermined distance from said run by particulate smoking material deposited on said run, thereafter further said smoking material being deposited on said run.
The present invention further provides, according to a second aspect thereof, a method of incorporating fibriform smoke-modifying material in smoking material rod, wherein fibriform smoke-modifying material is fed longitudinally thereof to a rod making machine, the feed path in said machine extending in the travel direction of the smoking material deposition run of the suction band of said machine, said fibriform material being constrained by guide means in said machine to follow said feed path spaced from said run of said suction band against the suction force towards said run until at a predetermined distance along said deposition run said fibriform material becomes supported and is subsequently maintained at a predetermined distance from said run by particulate smoking material deposited on said run, thereafter further said smoking material being deposited on said run.
The fibriform smoke-modifying material suitably takes the form of a single, continuous fibriform element. Alternatively, in respect of the second aspect of the present invention the fibriform smoke-modifying material could be fed to and into contact with the particulate smoking material in the form of a sequence of discrete fibriform elements. In the latter case each element, in the feed path of the elements, may be at each end thereof in contact with the respective ends of the next adjacent elements of the sequence thereof, or may be spaced therefrom.
In that particulate smoking material is deposited on the deposition run of the suction band both before and after the fibriform smoke-modifying material becomes supported at, or substantially at, the said predetermined distance from the run by smoking material on the run, in the carpet of smoking material as finally formed at the downstream end of the run the element(s) is disposed other than at the upper or lower boundary of the carpet. The position of the element(s) relatively of the upper and lower boundaries is determined in accordance with the location along the deposition run of the suction band at which the element(s) becomes supported by the smoking material deposited on said run. Suitably, the said location is selected to be in a mid zone of that portion of the deposition run which extends from the location at which smoking material is first deposited on the deposition run to the downstream location at which the carpet of smoking material is finally formed, i.e. the location at which deposition is terminated. Thus, for example, tee said location may be situate between about 25% and about 60% of the length of the said portion of the deposition run as taken from the location at which smoking material is first deposited on the run, and preferably between about 25% and about 40% of that length.
Suitably too, if the fibriform smoke-modifying material takes the form of a single only, continuous fibriform element, the feed path of the fibriform element in the making machine is aligned, or substantially aligned, with the plan view longitudinal centre line of the carpet on the deposition run of the suction band; that is to say, the element is, throughout the feed path thereof in the making machine, equi-distant, or substantially equidistant, the suction band guide rails of the machine. As will be readily apparent to those of ordinary skill in the art, if two, say, continuous fibriform elements are fed to the making machine, the respective feed paths thereof are in the proximity of the said longitudinal centre line of the carpet. By virtue of the said location being appropriately positioned in a mid zone of the said portion of the deposition run, and, in the case of a single element, the element being aligned with the aforesaid plan view centre line of the carpet, it may be readily arranged that the element extends axially of the subsequently formed smoking material rod.
According to the first aspect of the present invention the degree of ascent of the feed path of the fibriform smoke-modifying material is preferably only gradual (for example not more than about 5xc2x0 from the horizontal, and preferably about 1xc2x0 to 2xc2x0 from the horizontal). As will be realised by those skilled in the art, the degree of rigidity of the fibriform smoke-modifying material is to be selected such that the fibriform material is not, upon being exposed to said suction force, thereby immediately displaced upwardly onto the run of the suction band, but maintains a gradual ascent until at said predetermined distance along said deposition run the fibriform smoke-modifying material becomes supported by particulate smoking material deposited on the run. As will also be readily appreciated by persons skilled in the art, an important variable in ensuring that the fibriform smoke-modifying material initially becomes supported by the particulate smoking material deposited on said run at said predetermined distance along said deposition run is the distance between said fibriform smoke-modifying material at the point of entry thereof to the chimney of the making machine and the deposition run of the suction band.
According to the second aspect of the present invention, the feed path to which the fibriform smoke-modifying material is constrained by the guide means may extend at a constant vertical distance from the deposition run of the suction band. Alternatively, the guide means is so configured that the feed path ascends towards the deposition run, in which case the guide means terminates at the aforesaid distance from the deposition run, or somewhat short thereof. The path of ascent can be linear or, alternatively, the path of ascent can be curvilinear, an ogee curve for example.
Also, preferably the guide means of the second aspect of the present invention comprises rigid, elongate body means, which body means is provided with a guidance bore. The guidance bore is configured and dimensioned so as to ensure unimpeded movement through the bore of fibriform smoke-modifying material. Suitably, the elongate body is of generally tubular conformation. Thus, for example, the elongate body may take the form of a tube, the exterior diameter of which tube is suitably within a range of about 0.5 mm to about 3 mm in a case in which the fibriform smoke-modifying material takes the form of a single fibriform element. Conveniently, the exterior diameter of the tube is about 1.5 mm where it is the case that the single fibriform element is of an exterior diameter of about 0.5-1 mm. Thus it may be that the elongate body generally resembles a syringe needle.
Instead of the guidance bore being dimensioned appropriately for the movement therethrough of a single fibriform element, in the case in which two or more elements are fed simultaneously to the making machine, a single, larger guidance bore may be employed for the guided movement therethrough of the two or more elements in side-by-side disposition. Alternatively, each of the two or more elements is guided in a respective bore of a plurality of guidance bores. A single or plurality of elongate body means may provide the plurality of guidance bores.
Advantageously, the exterior conformation of the single elongate body means or the plurality thereof of the guide means is such as to minimise the obstacle presented, by the presence of the body means, to the flow of particulate smoking material to the deposition run of the suction band of the making machine. Thus, for example, a streamlined fairing may be provided, which fairing extends upwardly and/or downwardly of the elongate body means. Alternatively, or in addition, the flow of smoking material to the deposition run in the region of the guide means is aided by the provision of a modified flow path boundary configuration. Thus in the vicinity of the guide means the flow path to each side thereof may be enlarged, i.e. the lateral distance between the guide means and the path boundary to each side thereof is increased. In addition or as an alternative to these measures, the degree of suction at that portion of the deposition run overlying the guide means is modified relatively to that obtaining at the remainder of the deposition run. The degree of suction exerted in way of the guide means may, for example, be maintained at an elevated level and/or may be continuously varied.
Advantageously, the fibriform smoke-modifying element(s) is conveyed continuously to the point of entry to the rod making machine by feed means. The feed means may comprise a pair of opposed feed rollers, which rollers are operable to draw a fibriform element from a wound storage source thereof. Suitably, the speed of at least one of the feed rollers can be varied relative to speed of the rod making machine. Thus, the fibriform element is fed to the rod making machine at a fixed speed in relation to that at which the rod making machine is run.